The present invention relates to a system for controlling starting and stopping of an engine, and more particularly, to a system for starting and stopping an engine in response to a single push operation by a driver.
Generally, a vehicle is switched into a functional position by operating a key switch, which is arranged in the passenger compartment. The key switch is a rotary switch, which is rotated by an authorized key. The rotation of the key switch moves the switch between a movable contact and a fixed contact to select one of the functional positions, which are “OFF”, “accessory (ACC)”, “ignition on (ON)”, and “start (ST)”.
A manual push button switch is arranged in the passenger compartment of recent vehicles for a driver to start and stop the engine. An engine control system alternately starts and stops the engine whenever the manual button switch is operated. In a vehicle having both a manual button switch and a key switch, the driver must perform a rotating operation for switching to a functional position and a pushing operation for starting and stopping the engine. This results in the switches being inconvenient.
FIG. 6 shows a prior control system 61 for starting and stopping the engine. A power supply control unit 62 is connected to a start/stop switch 63, an engine control unit 72, and driver circuits 68, 69, 70, 71, which respectively activate an ACC relay 64, an IG1 relay 65, an IG2 relay 66 and an ST relay 67. In response to an operation signal from the switch 63, the power supply control unit 62 sends a control signal to each of the driver circuits 68-71 respectively to control activation of the associated relays 64-67. The power supply control unit 62 sends control signals to the driver circuits 68-71 and the engine control unit 72 to control the starting of the engine.
The power supply control unit 62 controls the starting and stopping of the engine when the operation signal is continuously received from the start/stop switch 63 for more than a predetermined time. When the operation signal is received from the start/stop switch 63 for a short time, the power supply control unit 62 switches functional positions. Therefore, if a manual button switch is used as the start/stop switch 63, the switching of functional positions and the starting and stopping of the engine are enabled by convenient single push operations.
The power supply control unit 62 is electronically controlled to activate and inactivate the relays 63-67. Therefore, when noise results in abnormal functioning of the power supply control unit 62, the relays 64-67 may also function erroneously. If the power supply control unit 162 functions abnormally when the vehicle is traveling and inactivates the first ignition relay (IG1) 65 and the second ignition relay (IG2) 66, the engine may stop.